Rare type of Bellini Duct Carcinoma in a Patient With Cacchi-Ricci Disease: A Case Report and Mini-Review

Medullary sponge kidney (MSK) is an uncommon kidney malformation, characterized by cystic dilatation of the precalyceal papillary collecting ducts. Urography and computed tomography scan represent the gold standard to detect this congenital disorder. A clear diagnosis is not always feasible, especially in the presence of a concomitant renal mass, which in turn can be difficult to detect in MSK patients. When conventional imaging is inconclusive, a renal biopsy can be considered in doubtful cases. Here, we report a unique case of a Bellini duct carcinoma in a patient with MSK and we review the literature on this complex condition.